Cancer is characterized by uncontrolled growth of cells coupled with malignant behavior: invasion and metastasis. It is a major cause of mortality in most industrialized countries. Different ways of cancer treatment can be used: chemotherapy, radiotherapy, surgery, immunotherapy and hormonotherapy.
Chemotherapy can be defined as the use of chemotherapeutic antitumoral agents to treat cancer. Broadly, most chemotherapeutic antitumoral agents work by impairing mitosis (cell division) or DNA synthesis, effectively targeting fast-dividing cells.
Chemotherapeutic antitumoral agents are delivered most often parenterally, noteworthy intravenously (IV) or intra-arterially (IA). IV or IA chemotherapy can be given over different amounts of time, depending on the drug and the type of cancer to be treated.
Hepatocellular carcinoma (HCC) is the fifth most common cancer in men (523,000 cases worldwide) and the seventh in women (226,000 cases worldwide), and most of the burden is in developing countries, where almost 85% of the cases occur, and particularly in men: the overall male/female ratio is about 4/1. The regions of high incidence are Eastern and South-Eastern Asia, Middle and Western Africa, but also Melanesia and Micronesia/Polynesia. Low rates are estimated in developed regions, with the exception of Southern Europe where the incidence in men (ASR 10.5 per 100,000) is significantly higher than in other developed regions (Globocan 2008, WHO, International Agency for Research on Cancer—IARC—, Cancer Incidence and Mortality Worldwide 2008).
There were an estimated 694,000 deaths from liver cancer in 2008 (477,000 in men, 217,000 in women), and because of its high fatality (overall ratio of mortality to incidence of 0.93), liver cancer is the third most common cause of death from cancer worldwide. The geographical distribution of the mortality rates is similar to that observed for incidence (Globocan 2008, WHO, International Agency for Research on Cancer—IARC—, Cancer Incidence and Mortality Worldwide 2008).
HCC usually occurs in people suffering from cirrhosis or chronic liver disease (CLD). All factors favoring the development of CLD or cirrhosis are consequently risk factors for HCC. The main etiologic factors are hepatitis B virus infection (HBV; 53%), hepatitis C virus infection (HCV; 25%), alcoholic liver diseases (ALD; 15-43%) or dysmetabolic disorders such as Non Alcoholic Steato-Hepatitis (NASH; 20%) obesity and diabetes. Other factors are less frequent: haemochromatosis, other chronic biliary or inflammatory liver diseases. Aflatoxins, produced by the fungi Aspergillus flavus and Aspergillus parasiticus grown on grains, peanuts, and other food products, are hepatotoxic agents and chronic exposure to these mycotoxins leads to development of HCC. The effects of chemicals are still debated and not prominent.
Current therapeutic strategies for HCC can be divided into curative treatments such as surgical interventions (tumor resection and liver transplantation), percutaneous interventions (ethanol injection, radiofrequency thermal ablation), or palliative treatments such as transarterial interventions (mainly transarterial chemoembolization or TACE), systemic therapies and experimental strategies (H. C. Spangenberg, R. Thimine, H. E. Blum, Biologics:Targets & Therapy, 2008, 2(3), 453). In carefully selected patients, resection and liver transplantation, allow a 5-years survival from 60% to 70%. Unfortunately, most patients in Western countries present an intermediate or advanced HCC at diagnosis, with the consequent inability to use these curative treatments (L. Faloppi, M. Scartozzi, E. Maccaroni, P. M. Di Pietro, R. Berardi, M. Del Prete, S. Cascinu, Cancer Treat. Rev., 2011, 37(3), 169).
Among palliative treatments, intra-arterial approach with chemoembolization (TACE) has shown to induce objective responses in 16-55% of patients, although many randomized trials did not show any survival benefit. Unfortunately, TACE is known to be often accompanied by severe side effects like hepatic failure or renal dysfunction (K. Kamada, T. Nakanishi, M. Kitamoto, H. Aikata, Y. Kawakami, K. Ito, T. Asahara, G. Kajiyama, J. Vasc. Interv. Radiol., 2001, 12(7), 847).
Until recently, for patients with advanced HCCs no therapy was available that prolonged overall survival (OS), indicating the need for new targeted-therapies (H. C. Spangenberg, R. Thimine, H. E. Blum, Biologics:Targets & Therapy, 2008, 2(3), 453). In 2007 and for the first time, sorafenib (Nexavar®), a multikinase inhibitor, showed an increase even modest, of the overall survival over placebo in patients with unresectable HCC. Beside this agent, various different molecules are currently tested in advanced stage HCC among which Brivanib, another oral multikinase inhibitor being currently tested in several phase III studies (H. C. Spangenberg, R. Thimine, H. E. Blum, Biologics:Targets & Therapy, 2008, 2(3), 453—K. Almhanna, P A Philip, Onco. Targets Ther., 2009, 18(2), 261).
Even though sorafenib is the standard of care for advanced stage HCC and is registered for the treatment of HCC without restrictions by the European Medicines Agency (EMA) and the Food and Drug Administration (FDA), the narrow inclusion criteria of the clinical trials leave many patients without proven efficacious treatment with regard to their disease stage. Moreover, since treatment failure happens in some patients on sorafenib, there still remains a medical need for those patients to improve treatment efficacy, drug regimen and overall tolerance, and to overcome resistance (M. Peck-Radosavljevic, Therap. Adv. Gastroenterol. 2010, 3(4), 259).
HCC is known as hypervascular solid cancer characterized by a high degree of drug resistance (T. Wakamatsu, Y. Nakahashi, D. Hachimine, T. Seki, K. Okazaki, Int. J. Oncol., 2007, 31(6), 1465). The mechanisms of this chemoresistance in HCC are multiple. However, the more common mechanism is related to the multidrug resistance (MDR) transporters, P-gp and MRP pumps (D. M. Bradshaw, R. J. Arceci, J. Clin. Oncol., 1998, 16(11), 3674. Review. Erratum in: J. Clin. Oncol., 1999, 17(4), 1330). These pumps allow tumour cells to efflux different types of chemotherapeutic agents into the extracellular environment (Y. Chen, S. M. Simon, J. Cell Biol. 2000, 148(5), 863). Chemoresistance related to the MDR phenotype may be intrinsic or be acquired during chemotherapy. Chemoresistance, whether spontaneous or acquired is a serious concern in cancer treatment. HCC is often intrinsically chemoresistant which is the major cause for failure of its therapy (R. Perez-Tomas, Curr Med. Chem., 2006, 13(16), 1859, Review). This poses a great obstacle in chemotherapy for cancer because higher doses of drugs need to be administered and in turn may cause severe adverse effects (F. Yan, X. M. Wang, Z. C. Liu, C. Pan, S. B. Yuan, Q. M. Ma, Hepatobiliary Pancreat. Dis. Int. 2010, 9(3), 287). Chemoresistance affects major chemotherapeutic agents and especially anthracyclins (like doxorubicin), vinca-alkaloids, epipodophyllotoxins or taxanes. The poor efficacy of chemotherapeutic agents attributed to the overexpression of the MDR gene underlines the need to develop new treatment strategies for HCC, which could take into account the resistance issues.
Doxorubicin is a chemotherapeutic compound, efficacy of which has been shown in several cancers including HCC. However, IV infusion of doxorubicin in HCC is modest with objective response rate of 5-10%. A large, randomized, multicentre clinical trial compared the efficacy of doxorubicin 60 mg/m2 administered through the IV route and thymitaq a direct thymidilate synthase inhibitor (Porta C., 2006). In the 446 randomized patients with unresectable HCC, the effect of doxorubicin was found modest. The modest effect of doxorubicin in HCC patients is assumed to result from multidrug resistance (MDR) mechanisms related to overactivity of PgP and MRP cellular pumps. Many strategies have been evaluated to overcome the resistance issues, including the use of Pgp and MRP inhibitors. The development of these drugs has been stopped due to their safety profile.
In HCC, new therapeutic strategies using cytotoxic agents were developed by hepatic intra-arterial (IA) injection in order to reduce the systemic toxicity, to induce important hepatic tumour necrosis and to save the healthy hepatic parenchyma.
The technology described in patents EP1056477, and its US equivalent U.S. Pat. No. 6,881,421, use polyalkylcyanoacrylate (PACA) polymer to formulate active ingredients into Nanoparticules. EP1056477, and its US equivalent U.S. Pat. No. 6,881,421, indicate the use of a complexing agent to complex the active ingredient during preparation of the nanoparticle so as to protect the active ingredient against chemical reactions that are necessary for the formation of the particle. Therefore, the active ingredient is advantageously associated in a non-covalent manner with the particle and protected from reactions or degradation. Nanoparticules comprising a pharmaceutically active ingredient, a polymer such as poly(alkylcyanoacrylate) and a complexing agent such cyclodextrins, are thus taught in EP1056477, and in its US equivalent U.S. Pat. No. 6,881,421.
Doxorubicin loaded in said Nanoparticules (hereinafter referred to as “Nanoparticules loaded with Doxorubicin”) is a drug formulation that associates a kind of PACA, polyisohexylcyanoacrylate (PIHCA), Nanoparticules with the chemotherapeutic agent doxorubicin.
Said Nanoparticules displays original mechanisms to bypass MDR that can be summarized as follow:
Nanoparticules loaded with Doxorubicin adsorbs to the surface of tumour cells and releases the entrapped doxorubicin close to the cell membrane which leads to a high local gradient concentration (Colin de Verdière A, Cancer Chemother Pharmacol. 1994; 33(6):504-8).
The nanoparticules degrade and release soluble polycyanoacrylic acid which might interact with the plasma membrane and contribute to improve the intracellular delivering of doxorubicin (De Verdière A C, Br J. Cancer. 1997; 76(2):198-205).
The soluble polymer could also mask the positive charge of doxorubicin thus preventing its effluxing by the Pgp (De Verdière 1997, Br J. Cancer. 1997; 76(2):198-205), acting as an ion pair without any covalent linkage). The direct interaction with MDR pumps (Pgp and MRP) is thus avoided.
In man, the efficacy and safety of Nanoparticules loaded with Doxorubicin through the hepatic intra-arterial route have been evaluated in 2 clinical trials: in one open phase I-II and one randomized phase II clinical trial (Table 1).
TABLE 1Summary of Study Designs for Clinical development of Nanoparticulesloaded with DoxorubicinPhase/PatientsStudyDe-Routeplanned/numberscriptionDosagePopulationcompleteStatusPhase I/IIOpenHepatic IAAdvanced21/20CompletedBA/2002/MC10 mg/m2HCC03/02SD20 mg/m2Esc dose30 mg/m235 mg/m240 mg/m2PhaseOpen,Hepatic IAAdvanced200/28 StoppedII/IIIMC30 mg/m2HCCBA/2006/Revery03/03PG4 weeksmax 3injections
The study BA2002/03/02 (phase VII study in patients with advanced HepatoCellular Carcinoma) was carried out according to a multicentre, open, dose-escalation design in patients suffering from HCC. Nanoparticules loaded with Doxorubicin was to be injected through hepatic intra-arterial (IA) route as a bolus. Successive cohorts of 3 patients were injected a single 10, 20 and 30 mg/m2 dose of Nanoparticules loaded with Doxorubicin. As the 30 mg/m2 dose was well tolerated, the protocol was amended to assess 40 mg/m2 and then 35 mg/m2. As these 2 doses were considered toxic, additional patients were given 30 mg/m2 Nanoparticules loaded with Doxorubicin dose in 15 minutes. Two patients received a second IA dose of Nanoparticules loaded with Doxorubicin and one patient received 3 IA infusions.
Twenty patients were included in this study. Apart from the serious respiratory TEAEs (Treatment Emergent Adverse Events) reported at 35 and 40 mg/m2, tolerance was acceptable; most of the TEAEs were short lasting and of mild severity. All were reversible without sequellae. Overall, 50% of the non-serious TEAEs were expected as already reported with free doxorubicin. The most frequent TEAE were leukopenia (n=13; 65%), neutropenia (n=12; 60%), nausea (n=10; 50%), anaemia and abdominal pain (n=9; 45%), asthenia, fever, alopecia (n=6; 30%) and cough (n=5; 25%). Increase in transaminases was reported in 11 patients (55%) and was expected as likely related to treatment efficacy. Two patients had serious Acute Respiratory Distress Syndrome (ARDS) at the Nanoparticules loaded with Doxorubicin dose of 35 mg/m2.
Efficacy data clearly demonstrated a signal of efficacy with a mean and median survival of 548 and 315 days respectively, an objective response rate of 65 to 80% according to clinical study criteria.
On the basis of these data, the efficacy and safety of an hepatic IA 15-minute infusion of Nanoparticules loaded with Doxorubicin was compared to those of standard of care treatment.
The second study BA2006/03/03 (Phase II/III study in patients with advanced HCC) was carried out according to a multicentre, comparative, open, randomized (with a 2/1 ratio) design in patients suffering from advanced HCC. Nanoparticules loaded with Doxorubicin was injected through IA route as a 15-minute infusion at the dose of 30 mg/m2, preceded and followed by an oral premedication with methylprednisone. Fifty patients were to be included in the 1st part of the study. Three Nanoparticules loaded with Doxorubicin infusions were to be received by 33 patients at 4-week intervals and each of the other 17 patients were to receive the best standard of care treatment adapted to the severity of the disease. At the end of this 1st phase, if Nanoparticules loaded with Doxorubicin was considered active in 2/3  of patients (patients free of local progression at 3 months), then 150 additional patients were to be enrolled.
This study was prematurely discontinued when 28 patients had been enrolled because of the occurrence of ARDS leading to death in 2 patients treated with Nanoparticules loaded with Doxorubicin. 17 patients had received 39 Nanoparticules loaded with Doxorubicin infusions and 11 were randomized in the control group. No patients died of ARDS in the control group.
Despite many patients in the Nanoparticules loaded with Doxorubicin group did not complete treatment according to the protocol (3 infusions 4-week apart) because of the premature discontinuation of the trial, 63% of patients in the Nanoparticules loaded with Doxorubicin group were free of local progression at month 3 (versus 75% showing local progression in the control group). The patients enrolled were monitored and survival was recorded up to February 2011. Overall survival was significantly longer in the Nanoparticules loaded with Doxorubicin group than in the control group. At this time point, the mean and median overall survival was 952 days for Nanoparticules loaded with Doxorubicin group versus 449 days for control.
In addition, survival was significantly much longer in patients having completed 3 courses of Nanoparticules loaded with Doxorubicin as requested in the protocol. The mean and median overall survival was twice as long in the Nanoparticules loaded with Doxorubicin group having received 3 IA injections as in the control group. Likewise survival was much longer in patients having completed 3 courses of Nanoparticules loaded with Doxorubicin than in those having received only one or 2 IA injections of 30 mg/m2 Nanoparticules loaded with Doxorubicin. These data confirmed the strong signal of efficacy of Nanoparticules loaded with Doxorubicin in the treatment of patients suffering from advanced HCC.
Hence, albeit very promising in term of efficacy, use of Nanoparticules loaded with chemotherapeutic drug, such as Nanoparticules loaded with Doxorubicin, in cancer treatment, and in particular HCC treatment, is not currently possible because of its severe pulmonary adverse events. New approaches allowing safer use, reducing the probability of occurrence of pulmonary adverse events and their severity under acceptable limits owing to the benefit/risk ratio are then needed. In particular, it would be very advantageous to decrease the pulmonary adverse events induced by these Nanoparticules and at the same time to maintain the good efficacy already observed.